Cargo or shipping containers, such as ISO containers, are commonly used to receive, store, and transport a wide variety of materials around the world by ship, truck and rail systems. When used to ship bulk cargo such as grains, bulkheads are installed at the cargo door(s) to constrain the cargo within the container. A plurality of horizontal bracing members, such as steel rods, are typically held within U-channels formed in opposing side walls at the container opening in order to brace the bulkhead against the bulk cargo. However, the steel bars are expensive and are subject to permanent deformation during bracing use.